Paper 1 Thermal Physics Route Answers

Q	Ans	Brief reason
1	B	Thermal equilibrium means no net heat flow and equal temperature.
2	C	$27+273.15\approx 300\mathrm{K}$.
3	B	Gas equations require thermodynamic temperature.
4	B	$E=mc\Delta T$.
5	B	Latent heat changes state without temperature change.
6	A	Internal energy is microscopic kinetic plus potential energy.
7	A	Ideal gas equation.
8	B	First law links $\Delta U$, heating and work.
9	B	Potential part of internal energy changes during phase change.
10	B	At fixed $V$, $p\propto T$ in kelvin.
11	B	$⟨E_k⟩=3kT/2$.
12	B	Heat loss means input energy overestimates useful energy, so calculated $c$ is too large.
13	B	Adiabatic expansion does work using internal energy.
14	C	Internal energy depends on state; heat/work are transfers.
15	B	Wall collisions produce pressure.
16	B	Thermal equilibrium requires equal temperature and no net thermal energy transfer.
17	A	The internal energy of a fixed amount of ideal gas is a function of thermodynamic temperature only.
18	A	Charles law in kelvin.
19	A	Heat is energy in transit due to temperature difference.
20	B	Constant-volume gas pressure extrapolates to zero.